Dispensed volumes of anti-asthmatic drugs related to the prevalence of asthma and COPD in Sweden.

Purpose: To explore the possibility of using dispensed volumes asthma/COPD drugs as a proxy for the combined prevalence of asthma plus COPD.

Methods: The proportions of the Swedish population with inhalation drugs for asthma/COPD 2004 were obtained using three different databases. A pharmacy record database gave the volumes of dispensed drugs (defined daily doses, DDDs of R03A + R03B drugs) for each patient, 20 years and older. The X-plain database of Apoteket AB gave drug sales data for Sweden and Swedish population data were obtained from Swedish statistics.

Results: The sales volumes of asthma/COPD drugs were much higher for older than for younger people. The volumes increased from 18 DDD/TID for the 20-29 year group up to 124 DDD/TID for patients 70-79 years, or about seven times. The average volumes per patient in the different age groups corresponded to one DDD/day in only three of the age groups (50-79 years). In the youngest group the average drug volume per patient corresponded to one DDD every second day, which may indicate undermedication. The percentages of the Swedish population with asthma/COPD drugs increased from 4.0% for 20-29 years old to 14.5% for 80+ years old, or 3.6 times. When head-to-head comparisons could be made between reported prevalence data of asthma and COPD and our data the two sets of data were in a reasonable agreement.

Conclusion: The prevalence of drug treatment, i.e. the proportion of the population with dispensed asthma/COPD drugs, could function as a proxy for the disease prevalence of asthma plus COPD.